Tutorial by Examples: l

Checking if a Variable Exists

You can check if a variable has been defined in a scope by using ColdFusion's built in StructKeyExists() function. This can be used inside a <cfif> tag to prevent error messages in the event you attempt to refer to a variable that does not exist. You can also use this function to determine whe...

coldfusion • Variables

Synchronous Producer/Consumer with BufferBlock

public class Producer { private static Random random = new Random((int)DateTime.UtcNow.Ticks); //produce the value that will be posted to buffer block public double Produce ( ) { var value = random.NextDouble(); Console.WriteLine($"Producing value: {value}...

.NET Framework • TPL Dataflow

Natural numbers in type algebra

We can draw a connection between the Haskell types and the natural numbers. This connection can be made assigning to every type the number of inhabitants it has. Finite union types For finite types, it suffices to see that we can assign a natural type to every number, based in the number of constr...

Haskell Language • Type algebra

Addition and multiplication

The addition and multiplication have equivalents in this type algebra. They correspond to the tagged unions and product types. data Sum a b = A a | B b data Prod a b = Prod a b We can see how the number of inhabitants of every type corresponds to the operations of the algebra. Equivalently, we...

Haskell Language • Type algebra

Return list from subroutine

You can, of course, return lists from subs: sub foo { my @list1 = ( 1, 2, 3 ); my @list2 = ( 4, 5 ); return ( @list1, @list2 ); } my @list = foo(); print @list; # 12345 But it is not the recommended way to do that unless you know what you are doing. While th...

Perl Language • Lists

Simultaneous debugging sessions with PhpStorm

Usage Sometimes, you could have to debug code in another PhpStorm project, you have to update the configuration. PHP configuration In php.ini, edit file and put xdebug.remote_autostart = 1 PhpStorm configuration You also have to configure your IDE: In the phpStorm configuration, Max. sim...

phpstorm • Debug with PhpStorm and Xdebug

Multiply defined function

The most important consequence of the One Definition Rule is that non-inline functions with external linkage should only be defined once in a program, although they can be declared multiple times. Therefore, such functions should not be defined in headers, since a header can be included multiple tim...

C++ • One Definition Rule (ODR)

Segfault analysis with GDB

Lets use the same code as above for this example. #include <iostream> void fail() { int *p1; int *p2(NULL); int *p3 = p1; if (p3) { std::cout << *p2 << std::endl; } } int main() { fail(); } First lets compile it g++ -g -o main m...

C++ • C++ Debugging and Debug-prevention Tools & Techniques

What is a valid function template overloading?

A function template can be overloaded under the rules for non-template function overloading (same name, but different parameter types) and in addition to that, the overloading is valid if The return type is different, or The template parameter list is different, except for the naming of paramete...

C++ • Function Template Overloading

Send simple email

This code sends a simple text-only email to [email protected] EXEC msdb.dbo.sp_send_dbmail @profile_name = 'The Profile Name', @recipients = '[email protected]', @body = 'This is a simple email sent from SQL Server.', @subject = 'Simple email'

Microsoft SQL Server • DBMAIL

Send results of a query

This attaches the results of the query SELECT * FROM Users and sends it to [email protected] EXEC msdb.dbo.sp_send_dbmail @profile_name = 'The Profile Name', @recipients = '[email protected]', @query = 'SELECT * FROM Users', @subject = 'List of users', ...

Microsoft SQL Server • DBMAIL

Send HTML email

HTML content must be passed to sp_send_dbmail SQL Server 2012 DECLARE @html VARCHAR(MAX); SET @html = CONCAT ( '<html><body>', '<h1>Some Header Text</h1>', '<p>Some paragraph text</p>', '</body></html>' ) SQL Server 2012 ...

Microsoft SQL Server • DBMAIL

Low-Variance Feature Removal

This is a very basic feature selection technique. Its underlying idea is that if a feature is constant (i.e. it has 0 variance), then it cannot be used for finding any interesting patterns and can be removed from the dataset. Consequently, a heuristic approach to feature elimination is to first re...

scikit-learn • Feature selection

Hello World

HTML <canvas id="canvas" width=300 height=100 style="background-color:#808080;"> </canvas> Javascript var canvas = document.getElementById("canvas"); var ctx = canvas.getContext("2d"); ctx.font = "34px serif"; ctx.textAlign = &qu...

html5-canvas • Getting started with html5-canvas

Trailing return type

auto is used in the syntax for trailing return type: auto main() -> int {} which is equivalent to int main() {} Mostly useful combined with decltype to use parameters instead of std::declval<T>: template <typename T1, typename T2> auto Add(const T1& lhs, const T2& rh...

C++ • auto

Order of initialization of globals across TU

Whereas inside a Translation Unit, order of initialization of global variables is specified, order of initialization across Translation Units is unspecified. So program with following files foo.cpp #include <iostream> int dummyFoo = ((std::cout << "foo"), 0); b...

C++ • Unspecified behavior

Creating an Interval Iterating System

A simple EntitySystem that processes a Family of entities not once per frame, but after a given interval. Entity processing logic should be placed in processEntity(Entity). For more info, please see IntervalIteratingSystem In the below code example, the best usage for this is the physics world ...

libgdx • Ashley Entity System

Ways to circumvent Same-Origin Policy

As far as client-side JavaScript engines are concerned (those running inside a browser), there is no straightforward solution available for requesting content from sources other than the current domain. (By the way, this limitation does not exist in JavaScript-server tools such as Node JS.) However...

JavaScript • Same Origin Policy & Cross-Origin Communication

Controlling the playback using SoundEffectInstance

SoundEffect.Play() plays the sound effect in a "fire-and-forget" fashion. The sound plays once and its lifetime is managed by the framework. You are not able to change the properties (volume, pan, pitch) of the sound during playback, loop it, position it in 3D or pause it. You can hold a ...

monogame • Playing Sounds

Installation or Setup

Google Sheets is a spreadsheet application that runs on web browser. It doesn't require any installation or setup just a Google account and a modern web browser.

google-spreadsheet • Getting started with google-spreadsheet